A bomb has killed at least six people and injured about 40 outside a concert hall in Stavropol, southern Russia.
Five women and a girl of 12 were killed when it exploded in the street minutes before a Chechen dance troupe were due to perform inside the building.
Prosecutors said the device appeared to have had the explosive power of about 200-250g (7-9oz) of TNT.
The ethnically Russian city lies close to the troubled North Caucasus but has largely escaped militant violence.
The bomb exploded on the busy street about 15 minutes before Chechnya's Vainakh state ensemble was due to perform inside the hall.
The concert was cancelled and the performers were returning to the Chechen capital, Grozny, a Chechen government official told Ruissian media.
Stavropol's governor, Valery Gayevsky, described the bombing as an "unprecedented, brutal provocation".
A city official said those injured included Russians, Chechens and Armenians.
A list of the dead and injured, with their names and ages, was published by Russian media.